Prenatal Treatment With Glucocorticoids Sensitizes the HPA Axis Response to Stress Among Full-Term Infants

The objective of this study was to determine the consequences for HPA axis functioning among healthy full-term newborns of prenatal treatment with the synthetic glucocorticoid (GC), betamethasone, which is the routine treatment for threatened preterm delivery. Ninety full-term infants were recruited into two study groups (30 betamethasone treated; 60 comparison group matched for GA at birth and sex). The cortisol and behavioral response to the painful stress of a heel-stick blood draw was assessed 24 hr after birth. Full-term infants exposed to prenatal betamethasone displayed a larger cortisol response to the heel-stick procedure, despite no differences in baseline levels. Further, within the recommended window of betamethasone administration (24-34 gestational weeks), infants exposed to betamethasone earlier in gestation displayed the largest cortisol response to the heel-stick. These data add to accumulating evidence that prenatal exposure to elevated GCs programs the development of the HPA axis. (C) 2010Wiley Periodicals, Inc. Dev Psychobiol 53: 175-183, 2011.